Confinement, entropy, and singleparticle dynamics of equilibrium hardsphere mixtures
Abstract
We use discontinuous molecular dynamics and grandcanonical transitionmatrix Monte Carlo simulations to explore how confinement between parallel hard walls modifies the relationships between packing fraction, selfdiffusivity, partial molar excess entropy, and total excess entropy for binary hardsphere mixtures. To accomplish this, we introduce an efficient algorithm to calculate partial molar excess entropies from the transitionmatrix Monte Carlo simulation data. We find that the speciesdependent selfdiffusivities of confined fluids are very similar to those of the bulk mixture if compared at the same, appropriately defined, packing fraction up to intermediate values, but then deviate negatively from the bulk behavior at higher packing fractions. On the other hand, the relationships between selfdiffusivity and partial molar excess entropy (or total excess entropy) observed in the bulk fluid are preserved under confinement even at relatively high packing fractions and for different mixture compositions. This suggests that the excess entropy, calculable from classical density functional theories of inhomogeneous fluids, can be used to predict some of the nontrivial dynamical behaviors of fluid mixtures in confined environments.
 Publication:

Journal of Chemical Physics
 Pub Date:
 October 2007
 DOI:
 10.1063/1.2795699
 arXiv:
 arXiv:0708.1955
 Bibcode:
 2007JChPh.127o4513M
 Keywords:

 61.20.Ja;
 65.20.+w;
 66.10.Cb;
 Computer simulation of liquid structure;
 Thermal properties of liquids: heat capacity thermal expansion etc.;
 Diffusion and thermal diffusion;
 Condensed Matter  Soft Condensed Matter;
 Condensed Matter  Statistical Mechanics
 EPrint:
 submitted to JCP